As a user equipment (UE for short) has continuously increasing functions, a user can access service data or download service data, such as audio and a video, to a UE anytime and anywhere by using a wireless network, which makes it more convenient for the user to listen to the audio and watch the video.
In the prior art, a process of accessing or downloading service data, such as audio and a video, by a UE is as follows. The UE sends a service request message to an access network device, the access network device sends the service request message to a core network device, and the core network device may send the service request message to a service provider (SP for short) by using a packet data network (PDN for short); the SP may send, by using the PDN, service data that is requested to be downloaded by the UE to the core network device, and then the core network device delivers the service data, such as audio and a video, to the UE by using the access network device; so that the UE completes the access or downloading process.